The synthesis of homochiral ligands based on [2.2]paracyclophane

A new ortho-lithiation of homochiral 4-N,N-diethylamido[2.2]paracyclophane 8 is the key to the production of a wide variety of 4,5-disubstituted homoc hiral ligands. psi -Geminal bromination of 8 proceeds in high yields and th e resulting bromide may be converted into a variety of 4,13-disubstituted l igands. The o-lithiation and psi -geminal reactions can be used sequentiall y to give 4,5,12-trisubstituted compounds in which two liganding groups hav e the same geometrical relationship as in 'Phanephos'(TM). Homochiral oxazo lines with only planar chirality have been made, one of which has been show n to be an effective catalyst for the Heck reaction. (C) 2001 Elsevier Scie nce Ltd. All rights reserved.